In a general cathode-ray tube, a high resistivity film is provided at the midpoint of a feed line from an anode provided for a funnel to an anode of an electron gun in order to lower the maximum instantaneous current at sparking inside a bulb, and to prevent the current from damaging the electron circuit connected to the electron gun, or the like. More specifically, as shown in FIG. 7, a conventional cathode-ray tube comprises a bulb 6 comprising a panel 2 having a phosphor 1 provided on the inner surface and a funnel 5 having conductive films 4a, 4b, and 4c provided on the inner wall 3, an electron gun 7 housed in a neck portion 5a of the funnel 5, and springs 10 having contact portions 9 to electrically connect the conductive film 4a on the funnel inner wall 3 with a final electrode 8. Numeral 24 indicates an anode terminal which applies high voltage to the final electrode 8 of the electron gun 7 through the conductive films 4a, 4b, and 4c.
The specific resistance value of the conductive film 4a at the neck portion 5a is set to be 0.1-1 .OMEGA.cm, the specific resistance value of the conductive film 4b at the cone portion 5b is set to be no more than 0.1 .OMEGA.cm, and the specific resistance value of the conductive film 4c between the conductive film 4a at the neck portion 5a and the conductive film 4b at the cone portion 5b is set to be 1-10 .OMEGA.cm respectively. The contact portions 9 of the springs 10 to contact with the conductive film 4a at the neck portion 5a are made of a metallic material having high conductivity, such as stainless steel. The above-mentioned construction lowers the maximum instantaneous current generated at a discharge inside the bulb 6, and protects the circuit parts of a TV set from malfunction or breakage (Tokkai Sho 59-171439).
In such a cathode-ray tube, however, the conductive films (4a, 4b, 4c) made of different materials are respectively formed on the funnel inner wall 3, so the cathode-ray tube has problems in connection, such as conductivity failures at the junction A between the conductive films 4a and 4c, and the junction B between the conductive films 4b and 4c, and stripping of the coating film. Another problem is the complicated production process since the different kinds of conductive films (4a, 4b, 4c) are respectively formed in a wide range at predetermined regions having different shapes on the inner wall 3 of the funnel 5.